With the development of mobile communication technologies, mobile communication devices such as mobile phones, tablet computers, laptops, or the like, are used more and more widely. Mobile communication devices with metal frames are preferred by people because of their fashion appearance as well as good durability.
Mobile devices normally use antenna systems to convert electric power into radio waves, and vice versa, so as to enable the mobile devices to perform wireless transmission and reception. However, a metal frame may bring an electromagnetic shielding effect against the antenna system of the mobile communication device. In order to improve a radiation space of the antenna system, in a related mobile communication device, the metal frame is configured to serve as a radiating part of the antenna system.
For example, the antenna system includes a metal frame and a system grounding unit connected to the metal frame. The metal frame is a ring-shaped metal frame surrounding the system grounding unit, and a ground line and a feed line are disposed on the metal frame. To enable the antenna system to have multiple available frequency bands, a plurality of radiation gaps may be formed in the metal frame of the antenna system, and the antenna system may feed to the radiation gaps directly.
However, a frequency band range of the above-mentioned antenna system with the radiation gaps is still narrow, and the radiation gaps formed in the metal frame may impact the appearance and integrality of the metal frame; moreover, the radiation gaps need to be formed by an extra manufacturing process, which increases an overall cost of the antenna system.
Therefore, it is necessary to provide a new antenna system which can overcome the aforesaid problems.